Fuse



Oct. 18,1927. E. L OGLE FUSE . Filed Nov. 9, 1925 l? Z, J

Patented ot.18,1927. Y

UNI-TED STATES ELMER Il. OGLE; OF CHICAGO,ILLINOIS, ASSIGNOR TO FEDERAL ELTECTRXC CGMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION OF ILLNOIS.

FUSE.

Application inea .november a, ieee.. ,semina 673,653. i

This invention `relates to overload circuit breakers, commonly known as fuses, adapted for use in multiphnse circuits, and consists of the matters hereinafter described and more particularly pointed out 'in the appended claim. y

The present application, which relates more specifically t'o the terminal construction on the fuse body for the wires by means tion in a plane at right angles to that of thev previous section, as indicated by the line 2-2 of Fig. 1.

Fig. 3 is a cross-section. through the fuse in a plane indicated by the line 3-3 of F ig. 1. i

Figs. 4, 5 and 6 are detail perspective views of parts to be more particularly dcscribed later. 4 A

Referring now to that embodiment of the invention illustrated in the drawings The fuse comprises a body 10 of insulation material, as fibre or the like, with metallic heads 11, 12, each carrying a blade contact 11a, 12a respectively. Enclosed in said body is a cartridge 13 containing fusible bars 14 (two as shown) and a heating coil unit 15 with terminals 16, 16 connected to spring contacts 17, 17 on the outside of the cartridge body.

The heating coil unit 15 consists of a narrow elongatedcore (seefFig. 2) comprising two outer sheets 18, 18 of asbestos, or like reproof material, and an intermediate sheet 19 of mica; of a coil of resistance wire 2O of the'required length, wound upon said core; and of two sheets 21, 21 of mica of substantially the same length as, but wider than the core, so that they project beyond each side of the core and beyond the ,i

coil wound thereon,-the several Sheets being securely attached together by means of metalrivets, which extend through theive thicknesses of material at or near the ends or the unit. rlhe ends ot'` the resistancewire are extended beyond the edges of the mica sheets 2,1, toprovide the terminals 16, 16 which extend through the cart-ridge wall and are connected to the spring contacts`17 as shown.

ln assembling the cartridge, the heating coil unit 15 is inserted into the cartridge and placed in a position adjacent to and parallel with the fusible bar or bars 14, a`nd`preter-V ably between said bars as shown, when two such bars are used. A tube of asbestos 22 is inserted within the cartridge body in advance ofi1 the insertion of the heating unitl and the heating unit, which is made somewhat nar-V rower than the innery diameter of the cartridge body, is held inplace by reason of the engagement of its lateral edges against the somewhat yielding inner surface of the asbestos tube. The powder in the cartridge alsol packsv against the outer faces of the heating unit, and acts to lockit in its proper position within the tube.v

Gn the fuse body are provided two termie nals or binding post constructions tor conv` necting to the fuse body`,the wires by means of which its heating coil 15 is connected to another circuit, (see Figs.y 1 and 3). As saidl terminals are ideifitical,` description of one" will suiic'e' for both. 23 infdi- Catesathreaded pini-or stud providedfw'ltll linward to engage one of the spring contacts 17 on the cartridge 13. A rectangular block or thimble 26 oi insulation material (shown in perspective in Fig. 41) vis engaged upon the stud 23. Said block or thimble has an apertured bo-ttom wall 27, flat on top and curved or concave on its bottom, as indicated at 28, to lit the cylindrical surface of the fuse body 10. lVhen the block is positioned upon the fuse body, the threaded pin 23 will extend through the aperture in said bottom wall of the block 26 and project a substantial distance above the same. The upright side walls 29, 29 of the block 26 above the bottom wall 27 are divided by diametrically opposite slots 30, 30. A thin fiat disc like nut 81 is threaded upon the pin 23 fromv its top end until it snugly engages the top surface of the apertured bottom wall 27, said nut coacting with the head 24 of the pin to tightly clamp the block upon the fuse body. To facilitate the threading of the lat nut upon the pin, said nut is provided with two oppositely disposed holes 32 (see Fig. 3) to receive the prongs of a small spanner wrench (not shown). A thumb nut or cap 33 is threaded on the pin 23 above the nut 3l, said cap consisting of an inverted tubular cup 34 constituting a head of hard rubber or other insulating` material, and of an internally threaded metal sleeve 35, fixed within said cup. The thumb nut is made of a diameter to it easily within the upright side walls 29 of the thimble. 36 indicates a washer which is engaged on the stud 23 between the nut 31 and cap 33. An end 37 of the wire leading to another circuit is looped about the stud 23, in the space between the nut 31V and the washer 36, whereupon the thumb nut'is screwed down to securely grip the said loop between the washer 36 and disc like nut 31. The block or thimble 26 extends considerably above the base of the thumb nut, when the thumb nut is screwed home, as clearly shown in Fig. l.

Each `insulation thimble 2G, by means oic its upright walls 29, presents a barrier or shield to prevent arcing in the gap between the terminal connection or' the wire 37 and theproximate metallic head of the fuse. It

for the Wires leading toI the heating coil of a fuse in another circuit, the fuse heads 11,

l2 are preferably each provided with a screw 38 and washer 39,-the latter having diametrically disposed upstanding lugs l0 (see Fig. G) which embrace the sides of the screw head and retain the wire terminal end in a familiar manner. The screws are threaded through the tubular parts of the heads into the fuse body and are located in the diametric plane of the blad-es v11, l2, as .shown in Fig. l. 'The block 26 in this case being rectangular in plan, instead of cylindrical as in the application before referred to, provides a stronger construction and a larger seat for the block upon. the fuse body.

I claim as my invention:

A terminal connection for an electric fuse comprising a thimble of insulation material having an apertured bottom wall concave on its bottom face to tit the body vof the fuse and flat on its top face, a threaded pin extending through the body of the fuse and through said apertured bottom wall, said pin having a head engaged against the inner surface ot the body ot' the fuse, a flat disc-like member operatively connected to the pin and engaged with the top face of said bottom wall of said thimble, the wall of said thimble above said bottom wall having diametrically disposed .slots located in a plane which is'at right angles to the central axis of the concave bottom face of said thimble, and a. thumb nut having a body of' insulation vmaterial adapted to iit within said thimble and being greater in height than the height of the wall of said thimble above its bottom wall, said thumb nut having kan internal metal threaded sleeve adapted to engage upon the outer Iend o't said pin. f

In testimony that I claim the foregoing as my invention, I aftix my signature this 31st day of October, A. D. 1923. f

lELMnR L. OGLE. 

